How to Choose Joint Compound

Setting-type joint compound, lightweight joint compound, all-purpose compound and others all have their unique uses. Learn the difference between them and get a better understanding of the choices for different situations.

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What joint compound to use when taping and repairing

Too many choices!

Lightweight “all-purpose”
compound and “easy-sand”
45-minute setting compound
are the two items novices
should load into their carts.
You'll find uses for all that other
stuff as your projects get bigger—
and you get faster and better.

Setting compounds

Setting compounds are dry powders that are mixed with water as needed. They harden in the time indicated on the bag.

For starters, buy a bag of 45-
minute setting compound; you'll
find it in 30-lb. bags (and sometimes
smaller boxes), with names
like Durabond or Easy Sand 45. It
comes as a powder—mostly plaster
of Paris—you mix with water as you
need it. It hardens quickly (you
guessed it, in 45 minutes), shrinks very little and dries hard as a rock.
This makes it ideal for filling oversize
cutouts around electrical boxes,
nail and screw dimples and cracks
in areas where drywall sheets don't
butt tightly. And since it dries
quickly, you can move on to the
“real” taping without waiting. Buy
an “easy-sand” variety; the standard
stuff dries so hard you can spend
hours sanding ridges left behind by
your trowel. Make sure to clean
your tools off pronto when you're
done unless you want a sculpture
titled “Drywall Knife Stuck in Pan.”

For embedding the tape and the
subsequent layers, buy lightweight,
all-purpose joint compound in the
familiar (and ever-so-useful) 5-gallon
bucket. This drying compound
hardens through evaporation—which means waiting up to 24 hours
between coats. Apply it full strength
across the joints and at corners for
bedding the tape. Then use it full
strength or slightly thinned for the
top layers. Try to avoid ridges and
bumps. But if you get them, don't
worry; the lightweight compound
sands easily. It also scratches easily,
so get a coat of primer on it as soon
as you can. It's worth the extra buck
per 5 gallons you'll pay for it. A
5-gallon bucket will finish about 450
sq. ft. of drywall, the equivalent of
fifteen 4x8 sheets.

What's all the other stuff on the
shelves? Topping compounds are
“soupy” and contain less adhesive
than all-purpose compounds. This
makes them easy to feather and
sand and thus ideal for the final
coat or coats. Some pros are fond
of this stuff, but for small jobs, all-purpose
is fine. The five- and 20-
minute setting compounds are used
by pros for filling gaps, bedding
tape, sometimes even for topcoats.
Time is money for these folks; they
can get away with using fast-setting
compounds because they know
how to apply them quickly and
smoothly with very little sanding.
But if you're a rookie, stay clear of
these; they'll harden before you can
walk across the room!